Preheat oven to 500 degrees F.
In a small saucepan over medium-high heat, bring water to a boil. Stir in couscous, cover, remove from heat, and set aside for at least 5 minutes.
Meanwhile, in a large skillet over medium-high heat, cook pork, stirring occasionally and breaking it up, until no longer pink, about 4 minutes.
Also while couscous is softening, remove tops from peppers and scrape out seeds. Set aside.
In a large bowl, combine couscous, pork, salsa, corn, and chili powder. Season with salt and pepper to taste. Fill peppers with pork mixture. Arrange peppers in a shallow baking pan and bake for 10 minutes.
Sprinkle cheese on top and continue baking until peppers are tender and stuffing is heated through, about 5 minutes.
Serve peppers with additional salsa on the side if you like.
Serves 4